(and there are those that contest it's account of the assassinations)

then you get a very detailed account of how the murders were planned, and executed

regardless of the fact it is a hell of a story that invites all kinds of interpretations

also, there is a wealth of writing on the subject and a large amount of conflicting information (ranging from issues over minor details on up to disputations over the key facts)

i haven't had a chance to see the film yet but from the trailer a number of the killings are in keeping with the accounts in Vengeance